In 3rd Generation Partnership Project Long Term Evolution (3GPP LTE), Orthogonal Frequency Division Multiplexing (OFDM) is adopted as a downlink (DL) transmission scheme.
The 3GPP LTE (Long Term Evolution) standard is the last stage in the realization of true 4th generation (4G) mobile telephone networks. Most major mobile carriers in the United States and several worldwide carriers have announced plans to convert their networks to LTE beginning in 2009. LTE is a set of enhancements to the Universal Mobile Telecommunications System (UMTS). Much of 3GPP Release 8 focuses on adopting 4G mobile communications technology, including an all-IP flat networking architecture.
The 3GPP LTE standard uses orthogonal frequency division multiplexing (OFDM) for the downlink (i.e., from the base station to the mobile station). Orthogonal frequency division multiplexing (OFDM) is a multi-carrier transmission technique that transmits on many orthogonal frequencies (or subcarriers). The orthogonal subcarriers are individually modulated and separated in frequency such that they do not interfere with one another. This provides high spectral efficiency and resistance to multipath effects.
The following documents and standards descriptions are hereby incorporated into the present disclosure as if fully set forth herein: 1) Document No. R1-101683, “Way Forward For PUCCH”, November 2010; and 2) Document No. R1-106557, “CR0270 Introduction of Rel-10 features”, December 2010.
In Release 10 LTE systems, a mobile station (or user equipment) performs feedback of precoder matrix index (PMI), rank indicator (RI), and channel quality indicator (CQI) to the base station (or eNodeB). The feedback content and signaling details for periodic channel state information reporting (PUCCH, CQI/PMI/RI reporting) within one component carrier are finalized in Document No. R1-101683. That is, three PUCCH feedback modes to be used are: submode 1 of PUCCH 1-1, submode 2 of PUCCH 1-1, and PUCCH 2-1. According to Document No. R1-106557, the following report types are supported in Rel-10:
Type 1 report supports CQI feedback for the UE selected sub-bands
Type 1a report supports subband CQI and second PMI feedback
Type 2, Type 2b, and Type 2c report supports wideband CQI and PMI feedback.
Type 2a report supports wideband PMI feedback
Type 3 report supports RI feedback
Type 4 report supports wideband CQI
Type 5 report supports RI and wideband PMI feedback
Type 6 report supports RI and PTI feedback